How do you reduce the effect of this interference on other system components like hard disk drives? Very simple – just don’t attach them to the connectors of the same power cable that the graphics card is attached to. Most PSUs have several cables for powering peripherals like HDDs, optical drives and others, so you shouldn’t feel any lack of them.
The oscillogram below shows the signal in the +5v line on the graphics card’s additional power connector in green, and the signal on the connector of other power cable in yellow. The units of the X and Y axes are 10 milliseconds and 50 millivolts, respectively. The graphics card works in the Burn mode:
The noise from the graphics card passes through the PSU and comes to the connectors of the other power cable much weakened. This is no surprise as any normal PSU has high-capacity output capacitors. Now, I take another oscillogram under the same conditions, but having attached the graphics card’s power not directly, but through the OCZ cable.
Attaching the OCZ cable into the graphics card’s power circuitry doesn’t change anything.
The “wondrous cables” from OCZ Technology do work. They do reduce the high-frequency interference that comes to the graphics card from the outside. Clearly, the cables will be as efficient working “the other way”: the interference from the graphics card will be diminished. That’s about all good that I can say on the topic of this small review. If you’ve got “stripes”, “snowflakes” or “waves” on the screen of your monitor due to electromagnetic interference in the graphics card’s power circuitry, these special cables from OCZ may help. Or they may not help. Graphics cards don’t get their power only through the additional power connector, but also through the AGP slot. The AGP slot receives its 3.3v, 5v and 12v voltages directly from the power connector of the mainboard. Of course, you can’t attach filters like the one implemented in the OCZ cable to these circuits.
The low-frequency noise generated by the graphics card in 3D modes is not practically diminished by the OCZ Power Leads. But it is considerably lowered by the PSU and this is one of the reasons why graphic card manufacturers don’t recommend using the same power cable for the graphics card and other system components.
So, the OCZ Enhanced VGA and HDD Power Lead kit looks nice, installs easily, can cause you no harm, and can do some good. Make your choice.